Using the eye muscle protein (EMP)-lipid vesicle system, perform serial studies of cell-mediated cytotoxicity in presence of thyroidal antigens in patients with Graves disease before and after 131I therapy or drug therapy, in close relatives of such patients, and in patients and other thyroid disorders. Define biochemically the ingredient(s) in eye muscle protein which facilitates vesicle lysis. Determine the factors affecting finding of thyroglobulin to specific components of eye muscle protein. Determine optimum conditions for spontaneous transfer of the TSH receptor from human thyroid cells in culture to lipid vesicles. Characterize the TSH receptor chemically. Develop a solid-phase assay for thyroid stimulating immunoglobulins (TSI) which is rapid, accurate, specific, and accommodating 100-200 samples per run. Prepare monoclonal thyroid stimulating immunoglobulin (TSI). Use this material to develop a new TSI assay based on specific binding of labeled TSI to purified TSH receptor.